[eclipse-cdt#719] Add required root files

* add SECURITY.md

SECURITY.md

@@ -0,0 +1,20 @@
+# Security Policy
+
+This project implements the Eclipse Foundation Security Policy
+
+* https://www.eclipse.org/security
+
+## Supported Versions
+
+These versions of C/C++ Development Tools (CDT) are currently being supported
+with security updates.
+
+| Version           | Released   | Supported | 
+| ----------------- | ---------- | --------- | 
+| 11.4.0            | 2023-12-06 | Yes       | 
+| < 11.3.0          | 2023-09-13 | No        | 
+
+## Reporting a Vulnerability
+
+Please report vulnerabilities to the Eclipse Foundation Security Team at
+[email protected]